Non-inflammable hydraulic fluid



United 1 NON-INFLAMMABLE HYDRAULIC FLUID Jones I. Wasson, Union, andArnold J. Morway, Clark,

NJ assignors toEsso Research and Engineering Company, a corporation ofDelaware No Drawing. Filed Sept. 14, 1955, Ser. No. 534,386 5 Claims.(Cl. 252-76) proposed. Some of these are of the hydrocarbon type whichare advantageous for many applications but which are rather highlyinflammable and unsuitable for certain uses. In industrial operation,such as the die casting of metals, for example, the control of the heavycasting machineryare operated largely by hydraulic means. The hydraulicfluids used in such controls have frequently been a source of fire anddanger. For this reason there is a growing demand for noninflammable,hydraulic fluids. Glycolwater base'type fluids have been investigated toa considerable extent for this application. These fluids are notabsolutely noninflammable but their resistance 'to flame is so much"greater than that of the hydrocarbon oils that they may be consideredsubstantially noninflammable.

,On the other hand, although the flame resistant prop with theglycol-water base. Unless the thickener is compatible, the solution isunstable, the thickener tending to settle out and to interfere withproper operation of the Y fluid or the mechanism in which his used.

Furthermore,j as suggested above, water base hydraulic fluids haverelatively very poor lubricating characteristics.

While hydraulic fluids are used primarily to'transmit forces throughhydraulic means, they must provide lubrication for hydraulic pumps andassociated mechanical parts in order topre'ventexcessive wear. The priorart hydraulic fluids of this type have been poor lubricants, on thewhole. Many of them have permitted rusting of ferrous metalswhichobviously is highly objectionable. Aside from the damage done by therust itself, the parts frequently stick, or freeze, 'so. that theoperation is uncertain [and erratic; In vital hydraulic controls, sucherratic o'perat ion'cannot be'tolerated at all and it isalwaysobjectionable in any'hydraulic mechanism.

It is known that certain of the long chain fatty acids and derivativesthereof have useful anti-wear and rust preventive properties when usedin hydrocarbon base oils. Thus, the use of oleic acid, stearic acid,lauric acid, the

" tent Patented Aug. 2, 1960 2 corresponding fatty oils or glyceridesand the like, in mineral base oils to reduce wear and also to helpinhibit rust is well known. These materials, however, are sub stantiallyinsoluble in water base hydraulic oils or fluids and are, therefore,unsuitable for use in the compositions of the present invention.

According to the present invention it has been discovered that acombination of glycol-water base fluid may be blended with a polyglycolor polyglycolether type polymeric thickener to improve viscosity andviscosity index, and a water soluble soap of an organic aliphatic acidmay be used to impart the other required properties. In particular awater soluble soap, preferably an alkali metal soap of a moderately longchain aliphatic acid, shows exceptional utility as an anti-wear andanti-rust agent.

The alkali metal soaps of straight chain fatty acids of C chain lengthor longer are substantially insoluble in Water. The branched chainsoaps, however, of acids having from at least 7 carbon atoms up to about14 carbon atoms are soluble in water, and soaps of highly branched acidsup to about C are soluble in the composi tions of this invention. Theymay be used to form stable blends having good wear preventingproperties,

5 branched chain acids and are obtained by subjecting vated temperaturesand pressures. Operable catalysts include the Well known cobaltcontaining catalysts, for example, cobalt, stearate, cobalt carbonyl,and the like. Pressures ranging from about 100 to about 300 atmospheresare used and a temperature in the rangeof about 200 to about 400 F. Theratio of hydrogen to carbon monoxide employed may vary betweenabout 0.5volume to 2.0, volumes of hydrogen 'per volume of carbon monoxide. i

The olefinic starting material preferably comprises olefins having frorn8 to 12 carbon atoms per molecule,

however, olefins having from 6 to; 24 carbon atoms may 1 be used. Theolefin is carbonylated in the process and r the resulting aldehydehasone more carbon atom the starting olefin. The process proceeds inaccordance with the following equatiom 7 r V 7 RCH=CH2+CO+HZWRCHPCHFCHOV a Ron-on.

one The aldehyde resulting from the carbonylat-ion of the olefin is.then oxidized to obtain the desired branched chain acid. This reactionis brought about by subjecting the aldehyde in basic solution to theaction of an oxygenating substance suchiasa; mixture ofnitrogen andoxygen (a irj)',. a material. releasing Enasc ent oxygen (KMnQ orthelike; 'Theoxidation reaction, one which is well known in the art,proceeds in accordance with the following equation:

i RCHz-CHz-CHO+[O1wROHr-CHr-(F-OH If desired, the Oxo reaction may becarried out in the presence of water in the form of vapor instead ofhydrogen. The desired branched chain acid is thus ob tained directlyfrom the x0 process. The same conditions of temperature and pressure arenecessary for this reaction as for the carbonylation reaction resultingin the aldehyde as described above.

Regardless of the manner of preparing the acid for the concept of thisinvention it is essential only that material be a branched chain acidand that it contain from 9 to 13 carbon atoms. 7 V Y The soaps of thesebranched chain acids are prepared by reaction of the acid with thedesired alkali metal hydroxide. Especially preferred are the sodium orpotassium soaps which have excellent water solubility and thus provideclear stable solutions.

' A preferred composition consists of about 40 to 65% by weight ofwater, about 9 to 34% of ethylene glycol, 20 to 30% of a polyglycol orpolyglycolether thickener of sufficiently high molecular weight toincrease the viscosity substantially, and 0.5 to 2% of the sodium soapof Oxo or other branched chain acids of the C to C range. The potassiumsoaps may be substituted for the sodium soaps and the proportion ofwater to ethylene glycol may be varied considerably depending upon theviscosity, pour point, freezing point, or other requirements.

EXAMPLE I A fluid containing 62.9% by weight of water, 11.1% of ethyleneglycol, 25% of a polymeric glycolether having a viscosity of about90,000 S.U.S. at 100 F., sold by Union Carbide and Carbon ChemicalCorp., under the trade name Ucon 75 H-90,000 1 was modified by additionof 1% of the sodium soap of a C 0x0 acid. This product had a viscosityof 290 S.U.S. at 100 F. and a viscosity index of 162.

EXAMPLE II A composition was prepared exactly as above except that 1% ofsodium soap of 0,, 0x0 acid was used as the modifier. Comparativelubrication tests were made using the 4-ball wear tester wherein threeball bearings, onehalf inch in diameter, are clamped in a holding deviceand a fourth ball is rotated so as to bear on the first three under anapplied load. This test of steel on steel was conducted at 167 F. undera 10 kg. load for one hour. In this test a glycol water base fluidcontaining only the polymer (no soap present) showed a wear scardiameter of 1.5 mm. after the one hour test. This is consideredexcessive wear. The same product containing 1% of sodium soap of C Oxoacid (Example I) showed a wear scar diameter of only 0.54 mm. which isfully equivalent to results obtained with mineral oils. The product ofExample II showed only slightly higher wear, 0.67 mm. scar diameter. Theblends containing the soaps also prevented rusting of steel specimensstored in the fluids for periods up to a month.

From the foregoing it is evident that the soaps are highly eifective forimparting anti-wear and anti-rust properties to the blends. Results aretabulated as follows:

A commercially available polyalkylene glycol prepared by Table I WearScar, Rust Test Fluid mm. in 4- Result Ball Test;

Example I 0. 54 N 0 Rust. Example II 0. 67 N 0 Rust. Fluid WithoutSoap 1. 50 Heavy Rust in less than 24 hours.

The quantity of soap which may be used may varywill depend upon itstype, but in general about to of a polyglycol ether type thickener ispreferred. These are highly suitable because of their excellentcompatibility with the glycols. In some cases as little as 5% up to asmuch as 40% of the-thickener may be employed. A preferred thickener isthe material mentioned above with a viscosity of about 90,000 S.U.S. at100 F. However, polymeric glycol ether products with S.U.S. viscositiessubstantially lower than 90,000, e.g., 400 and up to as much as 200,000S.U.S. at 100 'F., may also be '1 used. Some of the commercial productsin this class in- I alkali metal soap is a sodium soap.

clude Ucon H-490, Ucon 75 H-1400, and Ucon 75 H-9150 sold by the Carbideand Carbon Chemical Corp.

. It will be understood that additional conventional modifiers such asrust inhibitors, anti-foaming agents and the i for the same inventors.

What is claimed is:

1. A composition consisting essentially of about 40 to 65% by Weight ofwater, about 9 to 34% by weight of ethylene glycol, about 20 to 30% byweight of a polyalkylene glycol having a viscosity at of between thusobtained.

2. A composition according to claim 1 wherein said polyalkylene glycolhas a viscosity at 100 'F. of about 90,000 S.U.S.

3. A composition according to claim 2 wherein said 4. A compositionaccording to claim 2 wherein said branched chain acid contains 13 carbonatoms.

5. A composition according to claim 2 wherein said branched chain acidcontains 9 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS1,928,956 Tatter Oct. 3, 1933 2,553,364 Fasce May 15, 1951 2,558,030Zisman June 26, 1951 2,602,780 Zisman et a1. July 8, 1952 2,737,497Wasson et a1. Mar. 6, 1956 2,768,141 Langer Oct. 23, 1956

1. A COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 40 TO 65% BY WEIGHT OFWATER, ABOUT 9 TO 34% BY WEIGHT OF ETHYLENE GLYCOL, ABOUT 20 TO 30% BYWEIGHT OF A POLYALKYLENE GLYCOL HAVING A VISCOSITY OF 100*F. OF BETWEEN400 AND 200,000 S.U.S AND 0.5 TO 2.0% BY WEIGHT OF AN ALKALI METAL SOAPOF A BRANCHED CHAIN ACID CONTAINING FROM 9 TO 13 CARBON ATOMS, SAID ACIDBEING PREPARED BY THE CARBONYLATION OF AN OLEFINIC HYDROCARBON HAVINGFROM 8 TO 12 CARBON ATOMS WITH CARBON MONOXIDE AND HYDROGEN IN THEPRESENCE OF A COBALT CARBONYLATION CATALYST AT A TEMPERATURE OF ABOUT200 TO ABOUT 400*F. AND AT A PRESSURE OF ABOUT 100 TO ABOUT 300ATMOSPHERES AND THE SUBSEQUENT OXIDATION OF THE CARBONYLATED OLEFINSTHUS OBTAINED.